Abstract: Described herein are compounds and their use in the treatment of infections. The compound of formula (I), their derivatives, analogs, tautomeric forms, stereoisomers, polymorphs, solvates, pharmaceutically acceptable salts and pharmaceutical compositions described herein are also useful as ?-lactamase inhibitors, which restore or enhance the antibiotic spectrum of a suitable antibiotic agent. The compounds of formula (I) act as inhibitors of ?-lactamases. These compounds restore/potentiate the activities of ?-lactam antibiotics against carbapenemases. These compounds find use in diagnostic method for detecting ?-lactamases.